According to advance of plastic molding techniques in recent years, molded plastic articles have been diversified and further sophistication of the molded plastic articles has been required.
For example, there is a method of applying a sophisticated design to the molded plastic article by painting the surface thereof. The painting may be performed after the molding of the article by heat transfer, water transfer, screen printing and pad printing, or the painting and the molding may be performed simultaneously by insert molding [see Japanese Unexamined Patent Publication No. Hei 6(1994)-247058; Synthetic Resin, vol. 37, No. 5 (1991), etc.].
Some of the molded plastic articles require various properties such as resistance to scratching, antistatic property, hard coating or anti-reflective property, depending on their use. To meet such a requirement, there has been proposed a method of successively adhering layers each having the above-mentioned properties on the molded article (see Japanese Unexamined Patent Publications Nos. Hei 7(1995)-148881, Hei 10(1998)-235770; Hei 11 (1999)-326602, etc.).
According to the methods of painting the surface of the molded article or providing the functional layers on the molded article, however, the steps therefor are complicated, which reduces production efficiency and increases production costs so that low-priced final products cannot be obtained. Further, after the molding, it is difficult to paint or firmly adhere the functional layers to the molded article having a surface with a three-dimensional curve or minute unevenness, which leads to physical damages such as exfoliation of the layers.
On the other hand, according to the method of simultaneously performing the painting and the molding, steps thereof are simplified. However, to give the properties as described above, it is still necessary to adhere the functional layers to the surface of the molded article. That is, in the present situation, the reduction of the production costs and the prevention of physical damages for the functional layers have not been achieved yet.